JPS63118317A - Curing of polymerized composition - Google Patents

Abstract

PURPOSE:To obtain a cured coating film having excellent flexibility and elasticity, by producing an OH-containing modified copolymer from a caprolactone- modified vinyl monomer produced by the use of a specific catalyst and curing the obtained modified copolymer with a polyisocyanate crosslinking agent. CONSTITUTION:A hydroxyalkyl (meth)acrylate of formula I [R1 is H or alkyl; R2 is CmHm (m is integer of >=2)] is made to react with epsilon-caprolactone using a stannous halide of formula SnX2 (X is Cl, I or Br) as a catalyst to obtain a caprolactone-modified vinyl monomer of formula II (n is 0.3-50). A hydroxyl- containing caprolactone-modified copolymer is produced by copolymerizing 5-70wt% monomer of formula II with 95-30wt% radically polymerizable vinyl monomer. The obtained modified copolymer is crosslinked by the addition of a polyisocyanate compound having >=3 NCO groups at an amount to attain an equivalent ratio (OH/NCO) of 0.1-1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for curing a polymer composition by curing a modified copolymer having a hydroxyl group with a polyisocyanate crosslinking agent to form an excellent coating layer rich in flexibility and elasticity.

Acrylic paints have become increasingly important in the coating field in recent years.

The reason for this is that it has superior characteristics in terms of weather resistance, physical properties, chemical resistance, stain resistance, etc. compared to other coating resins, especially alkyd resins, polyester resins, epoxy resins, etc.

Therefore, acrylic coating compositions have come to be used in all fields such as automobiles, home appliances, metals, and building materials.

In addition, recently there has been a demand for energy saving, resource saving, and labor saving, and acrylic coating compositions that are high-solid and low-temperature curing have become necessary.

Furthermore, recently there has been a demand for high performance that cannot be applied with conventional coating agents, such as elastic coating agents for preventing cracks in organic elastic bodies such as urethane bumpers of automobiles, and cracking of mortar walls of plastic elastic containers.

In order to meet these demands, various improvements have been made to coating resins and their blended compositions.

Among acrylic resins, acrylic polyols, which are copolymerized with vinyl monomers having hydroxyl groups, are blended with crosslinking agents that can react with hydroxyl groups, such as polyisocyanate and melamine resin, and have been used in many fields. It has not yet reached the point where it can fully meet recent high-level demands.

Generally, hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl methacrylate, etc. are used as hydroxyl group-containing monomers when producing acrylic polyols, but when these monomers are copolymerized, the curing reaction with the crosslinking agent Since the hydroxyl groups involved are located close to the main chain of the rigid acrylic resin skeleton, the reaction with the crosslinking agent does not proceed sufficiently.

Therefore, even if the molecule a is made smaller in order to make the acrylic polyol resin highly solid, if the reactivity of water BN is insufficient, only unsatisfactory physical properties of the coating film can be obtained.

In addition, even if a soft acrylic polyol is synthesized by using a large amount of monomers that lower the glass transition temperature (To) in the acrylic resin component to obtain an elastic coating, the coating film may block due to the soft side chains, or the low temperature In order to improve such drawbacks, attempts have been made to graft-polymerize alkyd resins into acrylic resins.

However, the water RM of the alkyd resin is a secondary hydroxyl group with poor reactivity, and there is a significant drop in performance in terms of production power, weather resistance, water resistance, etc.

In addition, as an acrylic monomer having a hydroxyl group, 4-
It has also been proposed to copolymerize hydroxybutyl acrylate.

However, this monomer is expensive and its reactivity is still not sufficient.

Recently, a lactone-modified acrylic polyol in which ε-caprolactone is ring-opened and polymerized to the hydroxyl group of an acrylic polyol resin has been proposed.

This resin has a highly reactive primary hydroxyl group, and since this first water handling Wi group is located away from the main chain, it has high reactivity with the crosslinking agent.

In the production of this resin, conventional acrylic polyol resin was
- A method was adopted in which caprolactone was added and a ring-opening reaction was carried out in the presence of a catalyst (Japanese Patent Application Laid-Open No. 48-66194).

There is also a method of copolymerizing an acrylic polyol in ε-caprolactone, then adding a catalyst and ring-opening addition of the acrylic polyol (Japanese Unexamined Patent Publication No. 54-133
Publication No. 590).

In addition, ε-caprolactone, a vinyl monomer having a hydroxyl group, other vinyl monomers, a solvent, a radical initiator, and a ring-opening polymerization catalyst for ε-caprolactone are simultaneously mixed and heated to carry out ring-opening polymerization of ε-caprolactone and radical polymerization of the vinyl monomer. A method of performing both in parallel has also been proposed (US Pat. No. 4,082,816).

However, in these methods, the reaction temperature is limited by the boiling point of the solvent used to polymerize the acrylic monomer.

In commonly used solvent systems such as toluene and butyl acetate, the reaction temperature is 110-120°C, and at this temperature the ring-opening polymerization of ε-caprolactone to water iMM is extremely slow.

Therefore, in order to increase the reaction rate, a large number of open yA@cocatalysts must be used.

Metal compounds such as tin and titanium are generally used as ring-opening polymerization catalysts, which not only significantly discolors the resulting resin, but also has a negative effect on the long-term stability and performance of the coating layer when applied to paints. give.

Acrylic polyol resin is characterized by almost no coloring compared to other paint resins, and yellowish brown acrylic polyols are not suitable for practical use.

When using xylene or ethylene glycol acetate as a solvent, a reaction temperature of 140°C or higher can be used, but in this case, if a highly active titanium catalyst is used as a catalyst,
The transesterification reaction shown by the following formula occurs, which is undesirable.

↓Transesterification reaction In contrast to these methods, a vinyl monomer having a terminal hydroxyl group modified with ε-caprolactone, obtained by subjecting a vinyl monomer having a hydroxyl group to a ring-opening polymerization reaction with ε-caprolactone, is combined with another vinyl monomer to form a radical. There is a method of obtaining a lactone-modified polymer by carrying out radical polymerization in the presence of an initiator.

However, when carrying out the ring-opening reaction of ε-caprolactone to droxyethyl (meth)acrylate, which is the most commonly used vinyl monomer having a hydroxyl group industrially, conventionally used organotin-based catalysts, such as tin octylate, Dibutyltin oxide, dibutyltin laurate, etc. have weak catalytic activity, and if not used at several hundred ppm, ε-caprolactone and hydroxyalkyl (
The reaction of meth)acrylic acid ester does not proceed.

If a large amount of tin catalyst is contained in the resin, the pot life when polyisocyanate, which is a crosslinking agent, is added will be shortened and the resin will have no practical value.

Although the amount of catalyst used can be reduced by raising the reaction temperature, there is a risk that the acrylic ester will thermally polymerize during the reaction.

Other catalysts with strong catalytic activity include organic titanium compounds such as tetrabutyl titanate, tetrapropyl titanate, and tetraethyl titanate.

These have a catalytic activity about 10 times higher than that of organotin catalysts, and allow the reaction between ε-caprolactone and hydroxyalkyl (meth)acrylate to proceed even at relatively low temperatures.

However, these organic titanium compounds cannot be used because they have the following fatal drawbacks.

This is because organotitanium compounds not only have strong activity as catalysts for the ring-opening polymerization of ε-caprolactone to the hydroxyl group;
It also has strong activity against transesterification reactions.

Therefore, when an organic titanium compound is used as a catalyst to cause a ring-opening reaction of ε-caprolactone to a droxyalkyl (meth)acrylate ester, the transesterification reaction shown in the following formula proceeds at the same time, resulting in a di(meth)acrylate ester of a diol. is generated.

H3 If such a bifunctional (meth)acrylate is contained in a lactone-modified hydroxyalkyl (meth)acrylate, the polymerization reaction will be delayed when an acrylic copolymer is synthesized using this product as a raw material. During the process, the polymer thickens and eventually gels.

This is because three-dimensional crosslinking occurs due to the bifunctional acrylate.

Further, the reaction between ε-caprolactone and di-droxyethyl (meth)acrylate can also be carried out by using an acid catalyst such as sulfuric acid or paratoluenesulfonic acid.

However, it is undesirable for such strong acid catalysts to be included in the vinyl monomers, or even in the polymers in which they are polymerized.

This is because it acts as a reaction accelerator when crosslinking with the polyisocyanate curing agent, significantly shortening the pot life.

In addition, the transesterification reaction and etherification reaction between hydroxyl groups as mentioned above occur, and bifunctional monomers are produced as by-products.
In some cases, it is difficult to obtain the polymer itself.

In this way, water r! modified with ε-caprolactone! i
Although it is well anticipated that polyisocyanate-crosslinked coatings of vinyl polymers with M have excellent performance, there has been no good method for producing such polymers or monomers until now. .

In addition, as a curing method, there is a method using diisocyanate as a crosslinking agent, such as 56-44089, but it is well known that diisocyanate has a low boiling point and is extremely toxic to the human body. It is practically undesirable to use diisocyanate itself as a crosslinking agent.

As mentioned above, we have solved the drawbacks of the conventional technology and
- To establish industrially an excellent coating technology using isocyanate crosslinking of turnip O-lactone modified polymer,
As a result of intensive research, they were unable to complete the present invention.

That is, the present invention is a caprolactone-modified R+ vinyl monomer synthesized by the reaction of 5nX2 using stannous halide as a catalyst. -H or alkyl group R2=Cm82mm Integer value n of m≧2 -Average 0.3-50 A polyisocyanate compound having three or more isocyanate groups is added to a caprolactone-modified copolymer having a hydroxyl group, synthesized by OH/NCO, to give a ratio of Q of 1 to 10 (original ratio) for crosslinking. A method for curing a polymeric composition, characterized by:

The caprolactone-modified vinyl monomer, which is component a), which is necessary for synthesizing the caprolactone-modified copolymer containing 1 g of water used in the present invention, is synthesized by reacting the caprolactone-modified vinyl monomer with a stannous halide represented by 5nX2 as a catalyst. It is essential to do so.

is a hydroxyalkyl (meth)acrylic acid ester obtained by the reaction of methacrylic acid with monoepoxides such as ethylene oxide, brobylene oxide, butylene oxide, and α-olefin epoxide; Acrylic ester, hydroxypropyl methacrylic ester,
Hydroxypropyl acrylic wave ester, hydroxybutyl methacrylate, hydroxybutyl acrylate, etc. can be used.

It is also possible to use a mixture thereof.

That is, a compound of the general formula R1 (11L, R1H or OH3, R2 is CmH2m, and m is an integer of 2.3 or 4 or more.

ε-caprolactone is industrially produced by the Bayer-Villiger reaction of cyclohexanone with All, such as peracetic acid.

In addition, lactone compounds other than ε-caprolactone can be
It can also be used in combination with caprolactone.

The average value of n in the ε-caprolactone modified vinyl monomer represented by the above general formula is 0.3 to 50, preferably 0.5 to 5.

If the average value of n is larger than 50, the solubility of the acrylic copolymer in the solvent will deteriorate, which is not preferable.

For the reaction, a stannous halide represented by 5nX2 is used as a catalyst.

Specifically, stannous chloride, stannous bromide, and stannous iodide are used.

These stannous halides are characterized not only by their extremely strong activity as ring-opening catalysts for ε-caprolactone, but also by the fact that they hardly cause transesterification reactions.

In terms of catalytic activity, it is about twice as strong as the well-known tetrabutyl titanate and about 10 to 20 times as strong as that of organic tin compounds such as tin octylate.

Despite this, transesterification does not occur.

It is a side reaction product due to the Nisdell exchange of the ton reaction and is not produced at all.

Therefore, the lactone-modified hydroxyalkyl (meth)acrylate synthesized using 5nX2 as a catalyst does not contain difunctional di(meth)acrylate as an impurity, so even if this monomer is polymerized, it will not gel during the polymerization reaction. , a polymer can be obtained.

In order to obtain monomers with little coloring, stannous chloride and stannous bromide are particularly preferred.

The catalyst used is 1 to 1000 m for all preparations.
1)I)Ill Preferably 5 to 1100 pp.

The reaction temperature is 80-150°C, preferably 100-140°C.
It is ℃.

It is preferable to add a polymerization inhibitor to the reaction system. As the polymerization inhibitor, commonly used ones such as hydroquinone, hydroquinone monomethyl ether, and phenothiazine are used in an amount of 0.01 to 5% by weight, preferably 0.05 to 1% by weight.
Use within the range of 0i41%.

During the reaction, it is preferable to flow air or the like into the reaction system.

This is because polymerization tends to occur when an inert gas that does not contain oxygen flows.

Examples of radically polymerizable vinyl monomers to be radically copolymerized with component a) ρ1 synthesized in this manner include (meth)acrylic acid alkyl esters (eg, methyl, ethyl, and propyl).

Butyl, isobutyl, 2-ethylhexyl, lauryl,
alkyl esters such as cyclohexyl).

(meth)acrylonitrile, styrene, substituted styrene,
Vinyl chloride, vinyl acetate, acrylamide.

In addition to N,N'-dialkylhydroxyethyl (meth)acrylic acid esters and monomers containing water [3], there are human O-oxyalkyl (meth)acrylic acid esters, such as hydroxyethyl (
meth)acrylic acid ester.

Hydroxypropyl (meth)acrylic acid ester.

Hydroxybutyl (meth)acrylic acid ester, aryl alcohol, N-methylolated acrylamide, hydroxyethyl vinyl ether.

Hydroxyethyl butyl maleate, or “Cardura-E” as a vinyl monomer with a carboxyl group
Monoglycidyl esters such as L (trade name, manufactured by Shell Chemical Co., Ltd.) and alpha olefin epoxide-AO
Examples include hydroxyl group-containing polymerizable monomers obtained by adding a long-chain α-olefin monoepoxide such as EJ (manufactured by Daicel Chemical Industries, Ltd.).

Alkyd resins or oil-free alkyd resins having roughly polymerizable double bonds can also be used.

Furthermore, vinyl monomers having carboxyl groups, such as acrylic acid, methacrylic acid, itaconic acid.

Fumaric acid, monobutyl maleate, crotonic acid, etc. can also be used.

The m used for these polymerizable vinyl monomers is 95 to 30
The weight percentage is preferably in the range of 90 to 50 weight percent.

The copolymers of the invention are prepared using conventional radical initiators, such as peroxides such as dibenzoyl peroxide, ditertiary butyl peroxide, tertiary butyl peroxybenzoate, dicumyl peroxide, or azobisisobutyl peroxide. Using azo compounds such as lonitrile and the like.

Furthermore, the degree of polymerization can be adjusted by adding a chain transfer agent such as mercapto.

Polymerization is usually carried out by solution polymerization, but it can also be carried out without a solvent.

Solvents include toluene, xylene, and butyl acetate.

Commonly used compounds such as ethyl acetate, methyl ethyl ketone, methyl isobutyl ketone, ethyl cellosolve acetate, butyl cellosolve acetate, etc. can be used.

In the production of a radical copolymer, first a solvent is charged into a reaction vessel, and after the temperature reaches a certain level while nitrogen is flowing, a monomer and a radical initiator are added dropwise for a certain period of time to carry out the reaction.

It is also possible to initially charge a portion of the solvent, monomer, and initiator into a reaction vessel, and then add the remaining portion dropwise.

In either case, radical polymerization methods used in the art can be employed.

Now, the caprolactone-modified copolymer having a hydroxyl group synthesized in this way is light in color and is no different from a normal radical copolymer that is not modified with lactone.

Moreover, since there are few remaining metal catalysts, it has little effect on the reaction with the curing agent.

The caprolactone-modified copolymer having water am
A polyisocyanate compound having at least 70% by weight of isocyanate groups is added to effect crosslinking.

Examples of polyisocyanate compounds having three or more isocyanate groups include polyhydric alcohol adduct type polyisocyanates produced by reacting one isocyanate group of a diisocyanate compound with a hydroxyl group of a polyhydric alcohol such as trimethylolpropane. There is a compound represented by formula (2).

There is also a trimer of diisocyanate obtained by reacting diisocyanate with water, such as the one shown in formula (3).

There is also a triisocyanurate compound (4) in which the diisocyanate itself is converted into 31.

Diisocyanate compounds that are raw materials for these polyisocyanates include ethylene diisocyanate, propylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate, 1,4-dimethylcyclohexane diisocyanate,
1-Methylcyclohexane-2,4-diisocyanate.

4.4'-methylene-bis-(cyclohexyl diisocyanate), 3-isocyanatomethyl-3,5,5-
Trimethylcyclohexyl isocyanate (isophorone diisocyanate), tolylene diisocyanate, 4.
4'-diphenylmethane diisocyanate, xylene diinocyanate.

Examples include dimer acid diisocyanate and tetramethylxylene diisocyanate.

Polyisocyanate compounds (2), (3), (4) manufactured using these diisocyanate compounds as raw materials
) are generally diluted with a solvent or are commercially available without a solvent.

In the present invention, a polyisocyanate compound is added as a crosslinking agent to a caprolactone-modified copolymer containing water Ml to cause crosslinking.

When the amount is more than ON/NGO-10, the crosslinking density is so low that sufficient physical properties of the cured product cannot be obtained.

If it is less than 0.1 OH/NGO-1, the isocyanate group becomes excessive and reacts with moisture in the air to generate carbon dioxide gas, which is preferable.

The crosslinking reaction between the caprolactone-modified copolymer produced by the method of the present invention and the polyisocyanate compound may be carried out using, if necessary, a tertiary amine such as ester amine, tributylamine, or dibutyltin dilaurate to accelerate the crosslinking rate. It is also possible to add organic tin compounds and the like.

The crosslinking reaction may be carried out at room temperature or under heating conditions.

The polymer composition obtained by the method of the present invention contains a solvent.

Auxiliaries, additives, such as flow additives, such as silicone oil,
Matting agents, suspending agents or antifoaming agents, as well as pigments, such as titanium oxide of the rutin type, zinc sulfate.

Zinc sulfide, antimony oxide, suitable carbon black,
Iron oxide, filtered pigments, etc. can be added.

In this way, ¥J! The 4N polymer composition can be used as a two-component urethane paint for metals and plastics.

It can be used as a coating agent for paper, etc.

The coating method can be applied by spraying, casting, rolling, or doctoring in various thicknesses.

The cured coating film of the coating composition obtained by the method of the present invention has extremely high elasticity and toughness, and has excellent chemical resistance such as water resistance.

Next, the method according to the present invention and the characteristics of the coating film obtained by crosslinking the copolymer obtained by the method will be described using Examples.

During this period, the division will increase the number of overlapping divisions.

Example 1 a) In a 4-tubular flask equipped with an air introduction tube, a thermometer, a cooling tube, and a stirring device, 2446 parts of 2- and droxyethyl methacrylate, 2146 parts of ε-caprolactone, 9 22.4 parts of hydroquinone monomethyl ether as a polymerization inhibitor 9. 0.225 parts of stannous chloride was added as a reaction catalyst, and the mixture was allowed to react at 120° C. for 13 hours while bubbling air to obtain lactone-modified 2-hydroxyethyl methacrylate.

The reaction rate of ε-caprolactone is 99.4%, and the hue is 1 (
Gardna), the content of n1 biological ethylene glycol dimethacrylate by transesterification was 0.71%.

b) 333 parts of butyl acetate, 333 parts of toluene, and 10 parts of tertiary butyl peroxide were placed in a 4-tubular flask equipped with a thermometer, reflux condenser, nitrogen gas inlet, and Wll wire, and the temperature was raised to 120°C. When the temperature reached ℃, 400 parts of styrene, 100 parts of methyl methacrylate,
100 parts of butyl acrylate, methacrylic II! 10 parts 9 400 parts of ε-Cub O lactone-modified 2-hydroxyethyl methacrylate synthesized in Synthesis Example 1 and 10 parts of azobisisobutyronitrile were added dropwise over 4 hours, and the reaction was maintained for an additional 4 hours until the solid content was reduced. 61.7%, Gardna viscosity (25℃
) is 2-2. Acid value is 5.28<unit KOHη/g...
(hereinafter omitted), hydroxyl value is 53.3 (unit: KoHIIrg
/g...hereinafter abbreviated) 1 A transparent resin solution having a hue of less than 1 (Gardna) was obtained.

Example 2 a) Example 1. Into a similar apparatus as in a) were added 545 parts of 2-hydroxyethyl methacrylate, 955 parts of ε-caprolactone, 3 parts of hydroquinone monomethyl ether as a polymerization inhibitor, and 0.75 parts of stannous chloride as a catalyst, and heated at 120°C while passing air. React for 2 hours and lactone denaturation
-Hydroxyethyl methacrylate was obtained.

The reaction rate of ε-caprolactone was 99.0%.9 The hue of the reaction product was 1 (Gardna), and the content of the by-product ethylene glycol dimethacrylate was 0.381% by weight.

b) Example 1. 333 parts of butyl acetate, 333 parts of toluene, and 10 parts of ditertiary butyl peroxide were placed in a 4-tube flask similar to b), heated to 120°C, and heated to 120°C.
When the temperature reached ℃, 400 parts of styrene, 1'OO part of methyl methacrylate, 100 parts of butyl acrylate, and 10 parts of methacrylic acid were added.

400 parts of lactone-modified 2-hydroxyethyl methacrylate of a) and 10 parts of azobisisobutyronitrile were added dropwise over 4 hours, and the reaction was continued for another 4 hours, resulting in a solid content of 60.1
%, Gardna viscosity is 21~z2 acid 1i[[i5.06.
Water B haze value 35.4. A transparent resin solution with hue>1 (Gardna) was obtained.

Example 3 a) In the same apparatus as in Example 1, 504 parts of 2- and hydroxyethyl acrylate, 496 parts of ε-caprolactone, 5 parts of hydroquinone monomethyl ether, and 0.1 stannous chloride were added.
The mixture was reacted at 110° C. for 13 hours while bubbling air to obtain lactone-modified 2-hydroxyethyl acrylate.

The reaction rate of ε-caprolactone was 99.3%, the hue of the 9 reaction product was less than 1 (Gardna), and the content of ethylene glycol diacrylate in the 01 organism was 0.38% by weight. b
) 333 parts of butyl acetate, 333 parts of toluene, and 10 parts of diterclipyl peroxide were charged into a 4-tubular flask similar to Example 1, and the temperature was raised to 120°C. When the temperature reached 120°C, 400 parts of styrene and 1 part of methyl methacrylate were added.
00 copies.

Butyl acrylate 100 parts, methacrylic Fi 10 parts 1
400ml of lactone-modified 2-hydroxyethyl acrylate obtained in Synthesis Example 3 and 20 parts of azobisisobutyronitrile were removed over 4 hours, and the reaction was continued for an additional 4 hours to reduce the solid content to 6.
0.1%, Gardna viscosity Y-Z, Mlil[i5.4
A transparent resin solution of 8.7[1 (illi56.3. hue>1 (Gardna) was obtained.

Comparative Example 1 a) 799 parts of 2-hydroxyethyl methacrylate, 701 parts of ε-Cab O lactone, 3 parts of hydroquinone monomethyl ether, and 0.15 parts of tetrabutyl titanate as a catalyst were placed in the same apparatus as in Example 1, and the mixture was heated while blowing air.
The reaction was carried out at 20°C for 16 hours to obtain lactone-modified 2-hydroxyethyl methacrylate.

The reaction rate of ε-caprolactone was 99.6 parts. The hue of the 9 reaction product was 2 (Gardna), and the content of ethylene glycol dimethacrylate in the 01 organism was 4.0% by weight.

b) Butyl acetate 333 in a 4 tube flask similar to Example 1
1 part, 333 parts of toluene, and 10 parts of ditertiary butyl peroxide were charged, and the temperature was raised to 120°C. When it reached 120°C, 400 parts of styrene, 100 parts of methyl methacrylate, 100 parts of butyl acrylate, and methacrylic M were added.
10 parts, 400 parts of lactone-modified 2-hydroxyethyl methacrylate of Comparative Example 18) synthesized using tetrabutyl titanate as a catalyst, 1 azobisisobutyronitrile
When an attempt was made to drop 0 parts over 4 hours, the acrylic copolymer could not be obtained because the viscosity increased and gelled 3 hours after the start of dropping.

Comparative Example 2 a) Into the same apparatus as in Example 1, 1816 parts of 2-hydroxyethyl methacrylate, 3184 parts of ε-caprolactone,
Add 10 parts of hydroquinone monomethyl ether and 0.5 part of tetrabutyl titanate and heat to 120°C while blowing air.
The mixture was reacted for 13 hours to obtain lactone-modified 2-hydroxyethyl methacrylate. The reaction rate of ε-caprolactone was 99.2%.

The color of the reaction product was 3 (Gardna), and the total amount of by-product ethylene glycol dimethacrylate was 1.1% by weight.

b) Butyl acetate 333 in a 4 tube flask similar to Example 1
1 part, 333 parts of toluene, and 10 parts of ditertiary butyl peroxide were charged, and the temperature was raised to 120°C. When it reached 120°C, 400 parts of styrene, 100 parts of methyl methacrylate, 100 parts of butyl acrylate, 10 parts of methacrylic acid, and tetrabutyl were added. When an attempt was made to drop 400 parts of the lacto-modified 2-hydroxyethyl methacrylate of Synthesis Example 5 synthesized using titanate as a catalyst and 10 parts of azobisisobutyronitrile over a period of 4 hours, the mixture gelled within 2 hours after the start of the dropwise addition. It was not possible to obtain an acrylic copolymer.

Application: Dry coating thickness is 30-50 microns on a polished mild steel plate with a thickness of 0.3-0.511III.

Drying conditions: 80°C for 60 minutes, then 50°C for 24 hours Example 4 Various polyisocyanates were added to the lactone-modified acrylic polyol resin obtained in Examples 1 to 3 and Comparative Example 2 and the acrylic polyol resin not modified with lactone. After compounding the compound and coating it on a steel plate, it was dried and cured to obtain a coating film.

Table 1 shows the properties of the coating film.

The resin of the present invention has excellent flexibility.

Shows solvent resistance and chemical resistance.

The film forming conditions are as follows.

Curing agent polyisocyanate 1) Shellanate 24A-100 (hexamethylene diisocyanate/1-120 biuret type adduct from Asahi Kasei Industries, Ltd.) 2) Takenate D-11ON (xylene diisocyanate-based polyisocyanate from Shikinichi Yakuhin Kogyo Co., Ltd.) 3) IPDI-71890 (tripartite of isophorone diisocyanate from West German Huls) Compounding ratio OH/NCO-1 Comparative Example 3 In a 4-tube flask similar to Example 1, 500 parts of butyl acetate, 500 parts of toluene, and 10 parts of ditertiary butyl peroxide were added.
400 parts of styrene, 100 parts of methyl methacrylate, 244 parts of butyl acrylate, 250 parts of hydroxyethyl methacrylate,
120 parts of a mixed solution of 10 parts of azobisisobutyronitrile
Radical polymerization was carried out by dropwise addition over a period of 4 hours at °C. Stirring was continued for an additional 4 hours to complete the reaction.

The obtained resin solution has a non-stock content of 50% and a hydroxyl value of 49KO.
HRg/l Ia value 2.9 KOHq/y, viscosity (Gardner) S9, hue 30 (API-IA>).

Claims (1)

[Claims] a) Formula (1
) Caprolactone modification represented by ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ Formula... (1) Vinyl monomer 5 to 70% by weight, provided that R1=H or an alkyl group R2=CmH2m An integer value of m≧2 n= Average of 0.3 to 50 1. A method for curing a polymer composition, which comprises adding a polyisocyanate compound having at least three isocyanate groups so that OH/NCO=0.1 to 1.0 (equivalence ratio) and crosslinking the composition.